relu-core/modules/rp/lib/doubleComputed.js

Core for bot

var base = require("./base");
var rpVariable = require("./variable");
var rpComputed = require("./computed");

module.exports = function rpDoubleComputed(d, fn, fnBack) {
	var computed = d.computed(fn);

	var p = rpVariable(computed._getUndependend());
	p.constructor = rpDoubleComputed;

	var computedBack = p.computed(fnBack);

	var computedChanged = false;
	var computedBackChanged = false;
	computed.onChanged(function() {
		if(!computedBackChanged && !computedChanged) {
			computedChanged = true;
			base.atAtomicEnd(transferValue);
		} else
			computedChanged = true;
	});
	computedBack.onChanged(function() {
		if(!computedBackChanged && !computedChanged) {
			computedBackChanged = true;
			base.atAtomicEnd(transferValue);
		} else
			computedBackChanged = true;
	});
	function transferValue() {
		if(computedChanged) {
			p.set(computed._getUndependend());
		} else if(computedBackChanged) {
			d.set(computedBack._getUndependend());
		}
		computedChanged = computedBackChanged = false;
	}

	p._addWeakRef(computedBack);
	computed.ref(p);
	computedBack.ref(p);
	p.onceDisposed(function() {
		computed.unref(p);
		computedBack.unref(p);
	});

	return p;
};

/*
computed -> d
computedBack -> p
*/